254 THE PHYSIOLOGY OF REPRODUCTION 



can also be induced voluntarily by stimuli conveyed from the 

 brain (i.e. by sexual emotion). It is interesting to note, there- 

 fore, that Budge ^ and Eckhard ^ were able to cause the penis to 

 erect by electrical stimulation of the cervical cord, the pons, 

 and the crura cerebri. The same result was obtained by Pussep 

 by exciting a definite region in the cerebral cortex. In this case 

 erection was followed by ejaculation.^ 



It is stated also that hanging and decapitation in Man 

 are sometimes followed by erection.* According to Spina,^ 

 who experimented on the guinea-pig, section of the spinal cord, 

 near the last costo-vertebral articulation, is invariably suc- 

 ceeded by erection and ejaculation. 



There are certain facts which seem to show that the 

 higher nerve centres exercise an inhibitory influence over the 

 sexual processes. Thus, Retterer* states that it is easier to 

 induce erection by external irritation in a dog whose spinal 

 cord has been cut through, than in a normal animal. 



Eckhard ' was the first to show that the penis in the dog 

 could be induced to erect experimentally by the stimulation of 

 certain nerves which he called the nervi erigentes. These nerves, 

 which are truly vaso-dilator, were found in the dog to arise from 

 the 1st and 2nd sacral nerves, and in some cases from the 3rd 

 sacral nerve also. Gaskell * showed that in the rabbit the 

 erector fibres leave the spinal cord by the anterior (and not by 

 the posterior) roots of the 2nd and 3rd sacral nerves. Morat * also 



^ Budge, " Uebei das Centrum genitospinale des Nervus sympathetlcus, " 

 Virchow's Archiv, vol. xv., 1858. ' Eckhard, loc. cit. 



^ Pussep, " Ueber die Gehirnzentren der Peniserektion und des 

 Samenergusses," Inaug.-Dissert., St. Petersburg, 1902. Abstract in Le 

 Phyaiologiste Russe, vol. iii., 1904. 



■• Gotz, • Uber Erektion und Ejaculation bei Erhangten," Inaug.-Dias., 

 Berlin, 1898. 



^ Spina, " Experimentelle Beitriige zu der Lehre von der Erektion und 

 Ejaculation," Wiener Med. Blatter, 1897. 



* Ketterer, Article " Erection," in Richet's Dictionnaire de Physiologie, 

 vol. v., Paris, 1902. 



' Eckhard, loc. cit. 



" Gaskell, " On the Structure, Distribution, and Function of the Nerves 

 which Innervate the Visceral and Vascular Systems," Jour, of Phys., 

 vol. vii., 1886. 



» Morat, "Les Nerfs Vaso-dilatateurs et la Loi de Majendie," Arch, de 

 Phys., 1880. 



